summaryrefslogtreecommitdiffstats
path: root/arch/sparc/kernel/signal_64.c
diff options
context:
space:
mode:
authorDavid S. Miller <davem@davemloft.net>2016-05-28 21:21:31 -0700
committerDavid S. Miller <davem@davemloft.net>2016-05-29 11:24:05 -0700
commitd11c2a0de2824395656cf8ed15811580c9dd38aa (patch)
tree1a2024f157752d35d4ac42807c6ca1da7b52b58c /arch/sparc/kernel/signal_64.c
parent9ea46abe22550e3366ff7cee2f8391b35b12f730 (diff)
downloadlinux-d11c2a0de2824395656cf8ed15811580c9dd38aa.tar.bz2
sparc: Harden signal return frame checks.
All signal frames must be at least 16-byte aligned, because that is the alignment we explicitly create when we build signal return stack frames. All stack pointers must be at least 8-byte aligned. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/sparc/kernel/signal_64.c')
-rw-r--r--arch/sparc/kernel/signal_64.c31
1 files changed, 20 insertions, 11 deletions
diff --git a/arch/sparc/kernel/signal_64.c b/arch/sparc/kernel/signal_64.c
index 39aaec173f66..5ee930c48f4c 100644
--- a/arch/sparc/kernel/signal_64.c
+++ b/arch/sparc/kernel/signal_64.c
@@ -234,6 +234,17 @@ do_sigsegv:
goto out;
}
+/* Checks if the fp is valid. We always build rt signal frames which
+ * are 16-byte aligned, therefore we can always enforce that the
+ * restore frame has that property as well.
+ */
+static bool invalid_frame_pointer(void __user *fp)
+{
+ if (((unsigned long) fp) & 15)
+ return true;
+ return false;
+}
+
struct rt_signal_frame {
struct sparc_stackf ss;
siginfo_t info;
@@ -246,8 +257,8 @@ struct rt_signal_frame {
void do_rt_sigreturn(struct pt_regs *regs)
{
+ unsigned long tpc, tnpc, tstate, ufp;
struct rt_signal_frame __user *sf;
- unsigned long tpc, tnpc, tstate;
__siginfo_fpu_t __user *fpu_save;
__siginfo_rwin_t __user *rwin_save;
sigset_t set;
@@ -261,10 +272,16 @@ void do_rt_sigreturn(struct pt_regs *regs)
(regs->u_regs [UREG_FP] + STACK_BIAS);
/* 1. Make sure we are not getting garbage from the user */
- if (((unsigned long) sf) & 3)
+ if (invalid_frame_pointer(sf))
+ goto segv;
+
+ if (get_user(ufp, &sf->regs.u_regs[UREG_FP]))
goto segv;
- err = get_user(tpc, &sf->regs.tpc);
+ if ((ufp + STACK_BIAS) & 0x7)
+ goto segv;
+
+ err = __get_user(tpc, &sf->regs.tpc);
err |= __get_user(tnpc, &sf->regs.tnpc);
if (test_thread_flag(TIF_32BIT)) {
tpc &= 0xffffffff;
@@ -308,14 +325,6 @@ segv:
force_sig(SIGSEGV, current);
}
-/* Checks if the fp is valid */
-static int invalid_frame_pointer(void __user *fp)
-{
- if (((unsigned long) fp) & 15)
- return 1;
- return 0;
-}
-
static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize)
{
unsigned long sp = regs->u_regs[UREG_FP] + STACK_BIAS;